I have both candida and CFS. The candida is probably the cause of my CFS, as candida purposely damages your immune system to enable it to grow more freely. Once you get the candida under control, your Chronic-Fatigue-Syndrome should improve. The magnesium deficiency is caused by your gut not absorbing nutrients properly, again due to the candida. Once you have a deficiency, you can't make it up with oral supplements. I can tell you that the magnesium shots are wonderful. I have much more energy and feel much better when I've been given them by my doctor. I would recommend that, once you get your levels up, that you start taking a supplement that includes both calcium and magnesium to keep them where they should be. (Don't take these supplements with any other supplements, as they will hamper the absorption of the other supplements.) I find it best to take them with meals.